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Daily Reports
Contents
Remote observations.
Shifts after Sep. 20th to be defined (all times in UT):
September 20th, Monday
Nico, Xavier, Martino, Ioannis:
Ioannis, Angel:
Starting at 23:40 (UT) with calibrations in total power using Uranus. Mean pointing offsets: 3, -7 arcsec. After focus (best value -0.15), the best beam sizes obtained are around 13 arcsecs in 1mm and 17.9 arcsecs in 2mm. After that, we tried a beam map on Uranus (20210921s7). Opacity was about 0.3 and the humidity level very high (99%). The weather conditions are not so good, probed by the peak-to-peak variations of the baselines (up to +/- 5 Jy). We proceed with a calib_1scan on Uranus (s8). Then we go to NGC7027 and do pointing and focus. Then calib_1scan to NGC7027, CRL2688, MWC349 (s16 to s18). Then we proceed to the quasar 2251+158 for pointing, focus (best value -0.1), again pointing with best beam size ~18 arcsecs at 2mm and then a beam map (s26). Latest polami observations in July measured ~5 Jy at 3mm and ~2 Jy at 1.3mm for this source. NIKA2 pointing gives ~4 Jy at 2mm. Weather radar shows that (electric) storms are approaching. After this beam map, we do a skydip (s27). Then we go to HLTau for pointing (~18 arcsecs at 2mm) and calib_1scan (s29). PIIC and IDL give very different pointing results. IDL has a very large value in azimuth, so we select the PIIC result. Try again to point on HLTau with nkpointf and IDL results are in better agreement with PIIC, but the fit is not very good, possibly due to deterioration of weather conditions (peak-to-peak variations of baselines are about +/- 10Jy). Then we go to 0529+075 for pointing (~18.3 arcsecs at 2mm) and to ALFORI for calib_1scan (s32). HLTau and ALFORI are faint but observed as a test to check if they "survive" in the calibrators catalog. Finally we stop at 05:30 (local time) due to weather conditions deteriorations.
NP: Thank you Ioannis and Angel for these observations and the summary. I checked the IDL results on HLTau pointing for a bug that would lead to abnormal azimuth correction. I see the misunderstanding. In the terminal, the output of IDL is the pako command for convenience "IF A2 PROFILES ARE NICE". Which is not the case for this scan. In such case, the user may refer to the above lines in the terminal "If A2 profiles cannot be used, then you may try values derived on the maps", that give "Array 2: set pointing 7.0 -6.7", in good agreement with the corrections derived by PIIC.
IM: Thank you Nico for the clarification. This makes the issue clearer and the pointing corrections are indeed in good agreement. We make a note to check the A2 profiles and proceed according to your guidelines.
September 21th, Tuesday
Angel:
Starting at ~21:30 (UT). Problems with nika2-a VNC desktops: fixed by Gabriel (AoD) & Dave. Pointing and focus on Uranus. As planned, we got additional pointing offsets on several sources: Neptune, 2251+158, G34.3. On average, offsets are about 2.8, -9.2 arcsec. Mean tau(225 GHz)~0.55 over this pointing monitoring. Resonances reworked looking to reduce the raw number of bad KIDs (A1, A2, A3): 91, 14, 51. These numbers were inadvertently higher at the beginning of the session. Coming back to Uranus and new, careful pointing/focus corrections were obtained. Large opacity spikes after that. Waiting for a while. Beam sizes about 17.5" and 11.9" after pointing. A calib_1scan tried on Uranus (20210922s3): noticeable opacity increasing. A new calib_1scan on Uranus under a bit more stable conditions (s5); beam sizes of 17.4" and 11.8". Moving to Neptune. A calib_1scan (s8) after a pointing correction. Looks unstable. Ioannis taking over at 1:20 (UT).
Ioannis:
Begin on Neptune. First pointing shows very unstable conditions with baseline variations at +/- 15-20 Jy. Opacity continues to increase and being unstable, tau225 0.6-0.8 peak to peak, and humidity is very high (100%). Pointing and focus on Neptune improves the beam sizes slightly with best values 17.8" at 2mm and 12.0" at 1mm. Then tried a calib_1scan on Neptune (20210922s16). Then we move to NGC7027. Initial pointing shows low baseline variations at +/- 0.5 Jy but beam sizes look larger (14.2" at 1mm and 18.8" at 2mm). Taumeter plot shows large spikes and unstable tau225 values (0.6 - 0.8 peak to peak). A new focus shows much better results based on all focus criteria. After setting the best value (-0.9) the beam sizes are more or less unchanged (14.6" at 1mm and 18.7" at 2mm), so it is most likely due to weather deterioration or decreasing elevation (currently at 30 deg). Nevertheless, I try calib_1scan on NGC7027, CRL2688 and MWC349 before the sources go lower (s24, s25 and s26). On average, pointing offsets are about 2.4, -5.4 arcsec up to now. Next I went back to Neptune for pointing (good beam sizes: 11.8" at 1mm and 17.8" at 2mm) and one more calib_1scan (s28). Since the beginning of my shift, tau225 shows large variations (0.5 - 0.9 peak to peak). After that, I go to the quasar 2251+158 (3C454.3). After pointing and focus (have been focusing every ~1hr due to unstable weather conditions), the best beam sizes are 11.5" at 1mm and 17.5" at 2mm. Then I try a beam map on 2251+158 (s36), followed by a skydip.
September 22th, Wednesday
TBD:
September 23th, Thursday
TBD:
September 24th, Friday